Furnace stoker



H. E. PRESTON FURNACE STOKER 3 Sheets-Sheet 1v Filed Oct. 3,' 1953 Dec. 1, 1936. d H. E. PRESTON y 2,062,762

FURNACE STOKER Filed oct. s, 1955 s sheets-sheet;

Invenor Hey-eri E. Presin AZ Zorney Patented Dec. 1, 1936 UNITED STATES PATENT OFFICE FURNACE STOKER Application October 3, 1933, Serial No, 691,931

4 Claims.

This invention relates to improvements in mechanical stokers of the underfeed type, and more particularly to the fuel feeding rams and pushers associated therewith.

This invention contemplates improvements in the structure of the fuel feeding rams and push, ers of stokers of the stated character, and in the operating mechanisms therefor. In this respect a specic object of the invention is to provide a novel ram mechanism affording a reciprocatory movement of the ram with a minimum of componental forces angular to the normal line of movement, thereby reducing wear in the ram and load on the power mechanism. Another object of the invention is to provide a renewable ram construction in which those parts of the rain most subject to wear are detachable and renewable from the basic ram structure including the connecting rod journal. A further object is to provide an improved construction of the fuel pushing elements involving the provision of removable nose pieces for the individual pusher elements.

Other and further objects will become apparent as the description of the invention progresses.

Of the drawings:

Fig. 1 is a longitudinal section of the forward end of a stoker made in accordance with my invention.

Fig. 2 is a fragmentary plan View partly in section showing details of one of the rams and the immediately associated operating mechanism.

Fig. 3 is a sectional view taken substantially along line 3-3 of Fig. 2.

Fig. 4 is a plan View of one of the pushers.

Fig. 5 is a side elevational view of the pusher shown in Fig. 4.

Fig. 6 is a sectional view taken substantially along line 6-6 of Fig. 4, and

Fig. 7 is a sectional end view taken substantially along line 'I-'I of Fig. 5.

This application relates more particularly to fuel feeding r-ams and pushers of underfeed stokers, and is a continuation in part of my pending application Serial No. 425,316, filed February l, 19.30, now Patent No. 1,958,639 and assigned to the American Engineering Company.

Referring to the drawings, the front framework of the stoker consists, in the present instance, Yof a plurality of vertical beams I ,supporting a transverse horizontal composite beam 2, which in turn constitutes a support for the forward ends of rearwardly projecting brackets .3, to which are secured the ram boxes y4.

The rear ends of the boxes 4 are secured to and supported upon a series of vertical beams 5, which beams also constitute a forward support for the inclined beams 6, which constitute the main supporting 'frame for the stoker re- 5 tort structure designated generally in Fig. -1 by the reference numeral I. In the present instance the bottom of the retorts are composed of a plurality of fixed plates 8 and pusher elements 9, which are adapted for reciprocation be- 10 tween the plates Y8 after the manner well understood in the art and illustrated in the drawings. Journalled in the forward ends of the brackets v3 is a main actuating shaft I2, (Figs.

2 and 3), this shaft being provided with a se- 15 ries of cranks I3 which through connecting rods `I4 are connected with the rams I5 which operate within the boxes 4 in a well known manner to discharge fuel entering the boxes through hopper openings I6 into the upper ends of the re- 20 torts. At the .extreme upper ends of the retorts and immediately adjacent the mouth vof the ram cylinders, the sides of the retorts are provided with replaceable vwear plates Ill.

The construction of the rams is best illustrated ,25 in Figs. 1 to A3. `As therein shown, the rams individually comprise a hollow cylindrical portion II, which in assembly neatly land slidably yfits within a cylindrical liner I8, secured in the bore of the ram box, after `a manner well illustrated in Fig. 3. 30 The ram further comprises a base member I9 comprising a substantially annular flange 2|, from one face of which project into the interior of the cylindrical portion I'I a pair of extensions .22, .each of which including a journal 23 for the end of the connecting rod I4. The ange 2l of extensions .2,2 is longitudinally recessed, as shown in Fig. 3, for reception of the rod I4, and said recesses being so formed as to provide ample clearance allowance for the .angular movement of the 40 connecting rod. As shown in Fig. 3, ,thel extensions 22 in the assembled ram fit neatly within the hollow cylinder Il, which latter seats at one end against the face of the flange 2l, and the cylinder and base member are secured -together by 45 means tof a pair of screws 24 which, as shown in Figs. 2 and 3, pass through the outer end of the cylinder I-'I and are threaded into the en d of the extensions 22 o f the 'base `member I9. It will be noted that in this construction, aside from the 50 fact that the :cylindrical portion II, which is subject to greatest wear, may be detached and replaced that .the point of connection between the connecting rod :I4 and the ram is at a point approximately at the longitudinal center .of the ram 55 whereby the components of the thrust exerted on the ram through the connecting rod I4, which tend to twist the ram angularly with respect to its normal line of movement in the ram cylinder, are greatly diminished, thereby materially reducing wear, and also the power required for reciprocation of the ram within the cylinder. It will further be noted that in detaching the cylindrical portion |1 of the ram, it is unnecessary to detach the connecting rod I4 at the journal, it being sufiicient to release the screws 24 to permit removal n and replacement of the detachable part |1.

At opposite sides of the flange 2| are trunnions 25-25, which are respectively connected by the short connecting rods 26 with corresponding arms of bell crank levers 21, these levers being mounted one at each side of the ram boxes 4 upon the ends of a shaft 28 journalled in each instance in a bearing 29 depending from said boxes. See Fig. 3.

The other arms of the bell crank levers 21 are respectively connected through links 3| with the upper ends of bars 32, these bars being connected through a series of bell cranks 33 and links 34 with rods 35 connecting, as hereinafter set forth, with the pushers 9. The rods 35 are slidably mounted in guide brackets 36, these brackets being secured in vertical arrangement to the upright beams 5, as shown in Fig. 1. The brackets 36 are flanged and these flanges 31 through which the brackets are secured to the beams, abut one another and thereby close the spaces between the beams 5 to form a wall of the enclosure beneath the retorts which constitutes the air box of the furnace into which the draft air is forced, and from which the air passes to the fuel bed through the tuyres 38. The brackets 36 include extensions from both faces of the flanges 31, the inner extensions constituting guides for the rods 35, and the outer projecting portions forming aligned guides for crossheads 39 through which the rods 35 extend, and to the opposite sides of which the links 34 are attached. Those portions of the rods 35 which project through the outer extensions of brackets 36 carry sleeves 4| which constitute sliding bearings for the crosshead 39. The inner end of the sleeve 4| is threaded and receives a nut 42, this nut limiting the relative movement of the crosshead and the sleeve in one direction. The other end of the sleeve is also threaded for reception of a. collar 43, which collar is xed to the extremity of the rod 35 by means of a shear pin 44.

Intermediate the crosshead 39 and the collar 43, the sleeve 4| carries an outer sleeve 45, a washer 46 abutting the outer end of this sleeve, and one or a plurality of detachable substantially horseshoe-shaped elements 41, the latter constituting spacing washers which are readily detachable for adjustment purposes. The number and width of the washers 41, and the length of the sleeve 45 determines the extent of the lost motion between the sleeve 4| and crosshead 39, and assuming a given travel of the crosshead 39, the stroke of the rod 35.

For a more detailed disclosure of the elements just described reference may be had to my aforesaid application Serial No. 425,316.

The foregoing device provides ,a ready means for adjusting the stroke of the rod 35 and the pushers 9 associated therewith from the exterior of the furnace, and by means of the operating connection between the crosshead 39 and the shaft l2, and of the adjusting mechanism described above, it will be apparent that the stroke of each of the rods 35 may be regulated indeaoeave pendently of the stroke of the others. From the foregoing description, and with reference to Fig. 1, it will be noted that the pushers of the retorts, and the rams respectively associated therewith form operating units, affording a maximum flexibility in the relative adjustment of the various elements of which the unit is constituted.

With reference to Fig. 1, it will be noted that the lowermost of the bell cranks 33 includes a third arm 51 which connects through the medium of the link 58 with the crosshead 39 of the lowermost bracket, and through this crosshead with the lowermost of the rods 35. The uppermost of the rods 35 is connected through a link 59 with the cap pusher 9. The others of the rods 35, with the exception of the bottom, are connected through rods 6| with the respective pushers, the connection between the rods 6| and 35 being in each instance a flexible one by reason of fixtures 62, which are pivotally connected through pins 60 with the inner ends ofthe rods 35, the fixtures 62 also providing for elongating or shortening the overall length of the rods 6|.

At its inner end, each of the rods 6| carries a hook 63 which engages and grips a transverse pin 10 in the associated pusher. The connection between the rods 35 and the pushers is accordingly a highly flexible one rendering adjustment and demounting of the various elements a relativelyv simple one. The lowermost rod 35 is connected through a similar fixture 62 and rod 6| through suitable operating connections with an extension grate (not shown) The details of the pushers 9 are 'shown in Figs. 4 to '1 inclusive. Each of the pushers comprises a relatively open and light base frame 68 which constitutes the main rear portion of the pusher and which has openings 69 in which the pin 10 is mounted. The frame 68 has a forward extension 1| which constitutes a support for two detachable nose piece sections 12 and 13, these sections, as illustrated, fitting over the extension 1| forming each side thereof and overlapping along a longitudinal center line as indicated at 14 from a substantially solid fuel engaging nose for the pushers. The sections 12 and 13 in the present instance are corrugated or toothed at' the sides as indicated at 15, this formation in operation giving a desirable scraping action Vpreventing accumulations of finely divided fuel within the retort. The extension 1| of the base frame 68 also has at its forward end and on the under side a transverse recess 16 for a scraper bar which` operates upon the tops of the fixed plates 8. It will also be noted that each of the xed plates 8 is provided at the tip with a resilient scraper element 11 which engages and operates upon the top surface of the pusher nose. These last named sections are secured to the pusher frame by means of bolts 18, as illustrated, the device providing a. readily detachable and replaceablenose for the pushers. The scraper elements tend to prevent sifting of coal dust past the pushers.

While the structures herein described are admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to limit the invention thereto, but only by the scope of claims which follow.

What is claimed is:

1. A ram for mechanical stokers comprising a cylindrical portion open at one end, a body portion having a part exterior to said cylindrical portion and another part extending from said exterior portion into the interior of the cylinder,

means on the interior extension for attaching a 75 connecting rod to the ram, means for detachably securing the body and cylindrical parts together, and means on the exterior part of the body portion for attaching the ram to associated mechamsm.

2. A ram for mechanical stokers comprising a cylindrical section open at one end, a body portion having a flange adapted for abutment with the open end of said cylinder, a part extending from said ange into the interior of the cylinder, means on said interior part for attaching thereto a ramactuating rod, said ange portion being apertured for passage of said rod into the interior of the cylinder, and trunnions on said flange portion constituting a means for connecting the ram to associated mechanism.

3. A ram for mechanical stokers, comprising a cylindrical portion open at one end, and a body portion having a part exterior to said cylindrical portion arranged in abutting relation with the open end of said first mentioned portion, and another part extending from said exterior portion into the interior of said cylindrical portion, said last mentioned part comprising a pair of spaced parallel members, the inner ends of which being disposed in spaced relation with the closed end of said cylindrical portion, means secured to said parallel members for attaching a connecting rod to said ram, means extending through the closed end of said cylindrical portion and engaging the inner ends of said parallel members for detachably securing said body portion to said cylindrical portion, and means on the exterior part of said `body portion for attaching the ram to associated end of said cylindrical portion, means provided on said parallel member for attaching a connecting rod to the ram, bolt means extending through the closed end of said cylindrical portion engaging the inner ends of said parallel members for detachably securing said body portion to said cylindrical portion, and a pair of diametrically opposed trunnions extending laterally from said ange at substantially the longitudinal center line of said ram.

HERBERT E. PRESTON. 

